Marketable Securities (Narrative) (Details) |
Mar. 31, 2018
USD ($)
item
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Dec. 31, 2017
USD ($)
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|---|---|---|
| Schedule of Available-for-sale Securities [Line Items] | ||
| Fair value | $ 14,884,544 | $ 17,931,941 |
| Unrealized losses | $ 89,376 | $ 56,886 |
| 1 Commercial Paper With Unrealized Losses [Member] | ||
| Schedule of Available-for-sale Securities [Line Items] | ||
| Securities in a loss position, less than one year | item | 1 | |
| Fair value | $ 1,245,263 | |
| Unrealized losses | $ 1,758 | |
| 14 Corporate Bond Securities With Unrealized Losses Less Than 12 Months [Member] | ||
| Schedule of Available-for-sale Securities [Line Items] | ||
| Securities in a loss position, less than one year | item | 14 | |
| Fair value | $ 13,639,281 | |
| Unrealized losses | $ 87,618 |
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- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Number of investment positions in available-for-sale investments in a continuous unrealized loss position for less than one year or normal operating cycle, if longer, for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement. No definition available.
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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